The present invention pertains to a process for operating an incubator with at least one first temperature sensor for determining the temperature T1 in the interior space of the incubator, at least one second temperature sensor for determining the skin temperature T2 of the patient, a heating means for the incubator, and a measuring and control unit.
A process is described in DE 198 18 170 A1 according to which operating variables or parameters are determined for controlling the incubator from the linking of the temperatures measured on two skin areas of a patient, which skin areas have different temperatures, and the air temperature measured in the interior space of the incubator.
U.S. Pat. No. 3,920,000 shows a device in which a plurality of temperature sensors are linked with a downstream heating device via a measuring and control unit such that the heating device is switched off when a temperature limit value determined from the measured temperature values is exceeded.
Two different modes of operation have become successful for incubators so far in practice: According to the air temperature control, the set point of a preset air temperature in the interior of the incubator is compared with the measured value of a temperature sensor in the interior space of the incubator and the air temperature is set by a heating device as a function of the comparison. In the case of an air temperature exceeding a defined temperature limit value in the interior space of the incubator, the medical care personnel receives an acoustic or optical alarm.
In the case of skin temperature control, the set point of a preset skin temperature of the patient in the incubator is compared with the measured values of at least one temperature sensor on the skin of the patient and the heating device is set correspondingly in order to indirectly compensate the temperature deviation of the patient from the set point. In the case of a deviation of the measured air temperature from a preset temperature limit value, an acoustic or optical alarm is triggered.
One essential drawback of the prior-art process arises when the small patient is removed from the incubator to lie in direct skin contact on the body of the farther or the mother. This type of external care is called xe2x80x9ckangaroo carexe2x80x9d.
The skin temperature control leads to meaningless or even dangerous results in this case, because the incubator is set at false temperature values which are not caused by the temperature in the interior space of the incubator, due to the skin temperature sensors being on the outside. As a result, the patient is either heated or cooled too strongly when he is returned into the incubator. If the incubator is switched, instead, to the air temperature control mode before the beginning of the xe2x80x9ckangarooxe2x80x9d care, the skin temperature is not monitored, because the skin temperature alarm is active only when the incubator is operated by device of the skin temperature control. An air temperature alarm is frequently triggered at the same time, because the incubator is opened to remove the patient, so that cold air enters the incubator from the environment. However, this air temperature alarm is superfluous because the patient is already outside the incubator, so that the alarm must be switched off manually by depressing a corresponding operating control button.
The primary object of the present invention is to provide a process for operating an incubator which overcomes the drawbacks of the prior-art processes and makes possible the safe and reliable operation of the incubator.
According to the invention, a process and system are provided. The process and system are for operating an incubator with at least one first temperature sensor for determining the temperature T1 in the interior space of the incubator, at least one second temperature sensor for determining the skin temperature T2 of the patient, a heating means for the incubator, and a measuring and control unit. The process is activated by means of an input element at a time t0. The measuring and control unit regulates the heating device as a function of the temperature measured by means of a temperature sensor in the interior space of the incubator. The temperature measured in the interior space of the incubator during a preceding time period t0-t1 is used as the set point for the temperature in the interior space of the incubator. The skin temperature of the patient, which is determined by means of second temperature sensors, is compared with preset upper and/or lower temperature limit values for the skin temperature, An alarm is triggered by the measuring and control unit when limit values are overshot and/or undershot. An alarm circuit triggers an alarm as a function of the opening of the incubator and the associated temperature change in the incubator is deactivated for over a period t2-t0 following t0. The process is deactivated at the time t3 by means of the input element.
One or two temperature sensors may be used to determine the skin temperature of the patient and an alarm is triggered when the preset upper temperature limit values are exceeded. In the case of the presence of at least two second temperature sensors (to determine the sidn temperature), an alarm is triggered as a function of the comparison of the difference between the skin temperatures measured therewith and preset set points for the temperature difference.
The alarms may be deactivated during a period of up to 5 to 15 minutes after the time t0. The time periods t0-t1 and t2-t0 may comprise 1 to 15 minutes.
One essential advantage of the process according to the present invention is obtained due to the fact that the operation of an incubator becomes possible and false alarms are avoided under the above-described special conditions of the temporary removal of the patient from the incubator. This is accomplished with a structure that is known per se.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.